/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Tencent is pleased to support the open source community by making behaviac available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company. All rights reserved.
//
// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at http://opensource.org/licenses/BSD-3-Clause
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and limitations under the License.
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#ifndef _BEHAVIAC_BASE_RANDOMGENERATOR_H_
#define _BEHAVIAC_BASE_RANDOMGENERATOR_H_
#include "behaviac/base/base.h"

//#define _SYS_RANDOM_	1

#if _SYS_RANDOM_
#include <stdlib.h>
#endif//#if _SYS_RANDOM_

namespace behaviac
{
	class RandomGenerator
	{
	public:
		static RandomGenerator* GetInstance()
		{
			RandomGenerator* pRandomGenerator = RandomGenerator::_GetInstance();

			return pRandomGenerator;
		}

		//[0, 1)
		double operator()()
		{
			return this->random();
		}

		//[low, high)
		template <typename T>
		double InRange(T low, T high)
		{
			double r = (*this)();
			double ret = r * (high - low) + low;
			return ret;
		}

		void setSeed(unsigned int seed)
		{
			this->m_seed = seed;
#if _SYS_RANDOM_
			srand(seed);
#endif//#if _SYS_RANDOM_
		}
	protected:
		RandomGenerator(unsigned int seed = 0) : m_seed(seed) 
		{
			RandomGenerator::_SetInstance(this);
		}

		virtual ~RandomGenerator()
		{}

	private:
		static RandomGenerator* ms_pInstance;
		static void _SetInstance(RandomGenerator* pInstance);
		static RandomGenerator* _GetInstance();

		//[0, 1)
		virtual double random()
		{
#if _SYS_RANDOM_
			int v = rand();
			double r = v / (double)RAND_MAX;
#else
			m_seed = 214013 * m_seed + 2531011;
			double r = (m_seed * (1.0 / 4294967296.0));
#endif//_SYS_RANDOM_

			BEHAVIAC_ASSERT(r >= 0.0 && r < 1.0);
			return r;
		}

		unsigned int m_seed;
	};
}//namespace behaviac

#endif//_BEHAVIAC_BASE_RANDOMGENERATOR_H_